Helper to instantiate transient static values as required

4 files changed, 19 insertions, 9 deletions

diff --git a/game/scenary/foliage.cpp b/game/scenary/foliage.cpp
index 5902e09..f27ac26 100644
--- a/game/scenary/foliage.cpp
+++ b/game/scenary/foliage.cpp
@@ -4,6 +4,7 @@
 #include "gfx/gl/sceneShader.h"
 #include "gfx/gl/shadowMapper.h"
 #include "gfx/gl/shadowStenciller.h"
+#include "util.h"
 #include <location.h>
 
 static_assert(std::is_constructible_v<Foliage>);
@@ -40,12 +41,10 @@ Foliage::postLoad()
 {
 	texture = getTexture();
 	glDebugScope _ {0};
-	if (!(instanceVAO = commonInstanceVAO.lock())) {
-		commonInstanceVAO = instanceVAO = std::make_shared<glVertexArray>();
+	if (createIfRequired(instanceVAO, commonInstanceVAO)) {
 		bodyMesh->configureVAO(*instanceVAO, 0).addAttribs<InstanceVertex, &InstanceVertex::location>(1);
 	}
-	if (!(instancePointVAO = commonInstancePointVAO.lock())) {
-		commonInstancePointVAO = instancePointVAO = std::make_shared<glVertexArray>();
+	if (createIfRequired(instancePointVAO, commonInstancePointVAO)) {
 		instancePointVAO->configure().addAttribs<InstanceVertex, &InstanceVertex::location>(0);
 	}
 	const auto & size = bodyMesh->getDimensions().size;
diff --git a/game/scenary/illuminator.cpp b/game/scenary/illuminator.cpp
index e991baa..3b73cd3 100644
--- a/game/scenary/illuminator.cpp
+++ b/game/scenary/illuminator.cpp
@@ -1,6 +1,7 @@
 #include "illuminator.h"
 #include "gfx/gl/sceneShader.h"
 #include "gfx/models/texture.h" // IWYU pragma: keep
+#include "util.h"
 #include <location.h>
 
 static_assert(std::is_constructible_v<Illuminator>);
@@ -44,8 +45,7 @@ Illuminator::postLoad()
 	}
 	texture = getTexture();
 	glDebugScope _ {0};
-	if (!(instanceVAO = commonInstanceVAO.lock())) {
-		commonInstanceVAO = instanceVAO = std::make_shared<glVertexArray>();
+	if (createIfRequired(instanceVAO, commonInstanceVAO)) {
 		bodyMesh->configureVAO(*instanceVAO, 0).addAttribs<InstanceVertex, &InstanceVertex::location>(1);
 	}
 	if (!spotLight.empty()) {
diff --git a/gfx/renderable.cpp b/gfx/renderable.cpp
index 4597597..90035c3 100644
--- a/gfx/renderable.cpp
+++ b/gfx/renderable.cpp
@@ -2,6 +2,7 @@
 #include "gl_traits.h"
 #include "location.h"
 #include "maths.h"
+#include "util.h"
 
 std::weak_ptr<Renderable::CommonLocationData> Renderable::commonLocationData;
 
@@ -21,9 +22,7 @@ Renderable::CommonLocation ::operator=(Location const & location)
 
 Renderable::Renderable()
 {
-	if (!(locationData = commonLocationData.lock())) {
-		commonLocationData = locationData = std::make_shared<CommonLocationData>();
-	}
+	createIfRequired(locationData, commonLocationData);
 }
 
 GLuint
diff --git a/lib/util.h b/lib/util.h
index cd7971b..b60b093 100644
--- a/lib/util.h
+++ b/lib/util.h
@@ -3,6 +3,7 @@
 #include <algorithm> // IWYU pragma: keep
 #include <array>
 #include <cstddef>
+#include <memory>
 #include <tuple>
 
 template<typename T, std::size_t N>
@@ -33,3 +34,14 @@ template<size_t... N> inline constexpr auto Nth = GetNth<N...> {};
 inline constexpr auto GetFirst = Nth<0>;
 inline constexpr auto GetSecond = Nth<1>;
 inline constexpr auto GetSwapped = Nth<0, 1>;
+
+template<typename T>
+bool
+createIfRequired(std::shared_ptr<T> & instance, std::weak_ptr<T> & common)
+{
+	if (!instance && !(instance = common.lock())) {
+		common = instance = std::make_shared<T>();
+		return true;
+	}
+	return false;
+}